A FAILURE STRESS CRITERION FOR A POLYETHYLENE BALLOON FILM,
Abstract
As part of a study of stresses and deformations of balloon films, 'safe' stress levels for polyethylene balloon films are established. Various methods for the determination of the yield point and yield stresses are reviewed and their applicability to balloon films are discussed. In the present paper a 'safe' stress level is considered as the one at which the material sample which creeps will not fail within a specified time interval. Creep tests were conducted with cylindrical samples that were pressurized and additionally loaded by a dead weight axial load. It was found that within a narrow range of stresses, the deformation vs. time curves change from those of uniform creep to curves which show a highly accelerated rate of deformation. The stress values at which this abrupt transition takes place are considered as the 'failure' stresses. Using this new failure criterion a 'safe' stress chart for 2 mil StratoFilm is presented and its applicability in design and analysis of high altitude balloons is discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1968
- Accession Number
- AD0692516
Entities
People
- G. K. Narasimha Murthy
- Harold Alexander
Organizations
- New York University